Rainbow 320 does not drain when pump off

Good morning
am using Rainbow 320 while raising CYA
is a new one so check valve should be fine

directions say
1. Turn control valve to the closed position. SHUT OFF PUMP.
2. Wait one minute. This will allow water and fumes to drain from feeder.
3. Leave control valve closed and turn on pump. The check valve will prevent water from
entering the feeder.

but #2 seems to not be true, water does not drain

which is a problem cuz when you add tabs the water can splash or overflow and is nasty

contacted Pentair who said
1) relieve pressure by opening valve on the filter; did that and did not fix the problem
next suggestion was
2) unscrew Rainbow cap a bit, let water drain a bit, then screw cap back on
but that loses prime (I guess not a big deal but...)

any ideas why water does not drain as on the directions

searched but did not find "the answer"

by the way: tabs dissolve and feed Ok

thank you

Engrav,

Sorry I can't answer your question. I just wanted to mention that lately the staff here have been a bit short handed - you're not being ignored! Sounds like a plumbing question to me, but I could only guess and would add no value. Hopefully someone who knows a bit more on the subject will see your thread and respond soon.

I don't know much about inline feeders, but I've heard complaints that some of them clog...I didn't think the Rainbow was one of them, though. Ben (PoolDoc) is very familiar with that model, but, unfortunately, he's been very occupied with family matters, having just lost his dad.